TL and OSL preliminary studies on BeAl_2O_4: Cr~3 natural Brazilian mineral

摘要

The investigation of luminescent properties in alexandrite (BeAl_2_4:Cr~(3+)) in natural form is presented in this paper. Alexandrite is a rare and precious mineral that changes color according to the light incident on it. Moreover, in the synthetic form it is used technologically as active medium for laser, especially to its applications in the medical field, with properties superior to its main competitors, ruby and Nd:YAG. Sample composition is obtained through X-ray fluorescence measurements and, we present results of optical absorption. The work proposes to examine the behavior of thermoluminescence (TL) and Optically stimulated luminescence (OSL) signals, as well as their correlations. Initial measurements show that alexandrite sample exhibits low intensity TL peaks at 110, 160 and 280°C and a dominant peak at 350°C. For the first time an OSL study of the material is performed, showing an intense signal. In addition,probably Fe and Cr ions have an important part in the process TL and OSL.